[jqualls04GT]

I need to fix my rear end, and I want to get into autox as soon as I get my car setup the way I want it, not the PO.
The ring gear bolts installed w/ 4.10s by the PO rattled out and ate up the internals pretty good. So, I used some grade 5 bolts to get me back home. They are no longer bolts, but rather very short studs! So I figure since my carrier has a good ding/rip in it (about 1" starting at one of the openings) I am going to go ahead and upgrade to 31-spline axles. I can get the kit from LRS that has everything I need in it for ~$1090:1999-04 Mustang 8.8" 31 Spline Severe Duty Rear Axle Kit, 31 Spline, 4.10 Gears. But I'm not too sure about the locker for autox. Would I be better off with a 31-spline Trac-lok? Or some other diff? Besides Moser's $1k+ "wave action" or whatever it is. Thanks in advance.
When I start going to events, it won't be all the time, though, just hopefully once a month/ month and a half. I plan on going turbo eventually, so I probably won't be doing it very long, since boost isn't the best for autox (from a couple of thread s I've been reading through, but I have plans on alot more reading since I'm living on my ship for a while).

[ReverendDexter]

First thing I recommend is checking the rules for whatever class you're gonna run in where ever it is that you're gonna run. Some classes only allow you to keep the stock LSD, some updating and backdating within the same model (i.e. you can use any LSD so long as it came out of a Mustang), and some are totally open as to what you can do.

With that out of the way, I've heard really good things about the Torsen T2-R, though I have no personal experience with them. Last I checked, those were running about $600.

[jqualls04GT]

Thanks, RD, I decided I might as well upgrade to 31 spline axles. Especially since LRS has the diff on sale for less than $200! I'm getting a set of Richmond 4.10s for ~$140 and some ARP ring gear bolts (~$24). Now I'm looking at axles. I am probably going to go with Summit brand since they usually have top manufacturers make their parts; any thoughts on why I shouldn't do this? Only thing not ready for shipping is the axles and an install kit. I will probably get a cover later on after tow and registration funds.

[jqualls04GT]

Oh yeah, the car has less than 60k miles, since I got it w/ 62k on the clock and untuned 4.10s I put 5k on it in 3mos? I don't think so. So I'm not sure whether or not I should get an install kit with or without bearings. ? thanks.

A link to which kit to buy would be helpful as well! I am about to search the forums, but idk how much info I can turn up with that.

[01KnightRiderGT]

I would swap out the 4.10's for AX, you will find your self redlining 2nd all the time. For AX, your generally stay in 2nd gear. 3.73's would be a fine choice.

[ReverendDexter]

Just an FYI, Summit brand stuff usually is NOT top-brand stuff. It's usually whatever the cheapest of the name-brand stuff is. For instance, the mustang suspension parts they use are of a certain manufacturer of particularly ill repute.

I'd pay the extra for whatever LMR is selling. Summit's reputation is on having whatever part you're looking for and having it cheap, LMR's is on selling high-quality parts. Do you really want to have any question when it comes to the durability of your half-shafts?

I would definitely do the install kit and put fresh bearings in. You're already in there and messing with that stuff, might as well reset the clock on those parts as a while-you're-in-there.

And +1 to not just jumping to 4.10s. For typical AX courses, you're shooting to have your car redline at 60 mph in 2nd gear. That should make it so you never have to shift into third. If your group has faster courses (e.g. the group I run with typically has at least one part of the course that the faster cars can hit 70-75), then you may want the lower gears, as you'll be in 3rd anyway. I'd do some runs, see how fast you're actually going, and do the math as to what's gonna be best for you.

The flipside of gears is that you're likely traction-limited as it is. I know with a torque arm and Star Specs I can *still* spin the tires with 2.73s, and I only dyno at 194whp!